JPH11260255A - Dry film, and manufacture of shadow mask for color picture tube using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesion force by providing a cushion layer made of non-photosensitive coating film between a base film and a photosensitive coating film, thinning film thickness, and laminating them without entraining air, depending on recessed or projecting surfaces of a shadow mask material. SOLUTION: A dry film consists of a base film 20, a cushion layer 21 made of a non-photosensitive coating film provided on the base 20, and a photosensitive coating film 22 provided on the cushion layer 21. The base film 20 is a resin such as polyethylene terephthalate resin having adequate flexibility. The cushion layer 21 is made from at least one of polyvinyl alcohol and modified polyvinyl alcohol, and its film thickness is suitably 5-25 μm. The photosensitive coating film 22 contains a base polymer, polymerizable monomer, and photo-polymerization initiator or the like with a molecular weight of about 5,000-200,000 of a acrylic, metacrylic, or epoxy base, and its thickness is suitably 5-15 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dry film effective for manufacturing a shadow mask for a color picture tube and a method for manufacturing a shadow mask for a color picture tube using the dry film.

[0002]

2. Description of the Related Art In general, a color picture tube used for a TV image receiving apparatus or a display device such as a computer has a phosphor screen 2 comprising a three-color phosphor layer provided on an inner surface of a panel 1 as shown in FIG. A shadow mask 3 is disposed in opposition to the electron beam 7, and the three electron beams 7 B, 7 G, and 7 R emitted from the electron gun 6 disposed in the neck 5 of the funnel 4 are selected by the shadow mask 3 to correspond to the corresponding three. It is formed in a structure to be incident on the color phosphor layer. The shadow mask 3 has a large number of apertures formed in a predetermined arrangement on a surface facing the phosphor screen 2. The shape and size of the openings of the shadow mask 3 greatly affect the display characteristics, so that high accuracy is required.

[0003] Such a shadow mask 3 is conventionally manufactured by a photo-etching method.

[0004] That is, a thin metal plate made of low carbon steel such as aluminum killed steel or a low thermal expansion alloy such as Invar is used as a shadow mask material, and as shown in FIG. An object is applied and dried to form a photosensitive coating film 10. Next, a pair of optical masks 11a and 11b on which a pattern corresponding to the opening of the shadow mask is formed are brought into close contact with the photosensitive coating film 10 on both surfaces and exposed, and the patterns of the optical masks 11a and 11b are printed. wear. Next, the photosensitive coating film 10 on which the pattern is baked is developed to remove unexposed portions, and as shown in FIG. 2B, both sides of the shadow mask material 9 correspond to the openings of the shadow mask. Resists 12a and 12b composed of patterns are formed. After the resist is burned to improve the etching resistance, the shadow mask material 9 is etched from both sides to form the openings 13 as shown in FIG. Then, (d)
As shown in FIG. 2, the resist is peeled off on both sides to form a flat mask 14 having a flat shape.

In general, the production of this shadow mask involves
Liquid photosensitive compositions containing casein as a main component and ammonium bichromate added thereto are used.

[0006] Since the main component of this photosensitive composition is a natural product, it has advantages such as low cost, water solubility and low danger. However, when dichromate is used as a sensitizer, environmental pollution by hexavalent chromium ions becomes a problem. In addition, since it is a crosslinking reaction by ions, trivalent chromium ions generated by photoreduction are easily moved,
Dark reaction easily occurs. In addition, there is a problem that the film thickness tends to fluctuate, the edge of the pattern corresponding to the opening of the shadow mask of the developed resist is easily dropped, and an undesired opening shape is formed.

In order to solve the above-mentioned problems, a dry film in which a dark reaction hardly occurs because a film thickness is easy to be made constant and ions are not moved by a cross-linking reaction by radical polymerization. It has been proposed to use it.

This dry film is obtained by applying a photosensitive composition containing at least a base polymer, a photopolymerization polymer and a photopolymerization initiator on a base film and drying the composition to form a photosensitive coating film. By laminating this on both sides of the shadow mask material, a photosensitive coating film can be easily formed.

[0009] Such dry films are commercially available from various companies for patterning printed wiring boards and semiconductor lead frames. However, when they are used in the manufacture of shadow masks, the following problems arise. There was found.

[0010] (a) During the heat lamination, air does not escape completely, and bubbles are formed between the photosensitive coating film and the shadow mask material, which becomes a defect during etching. (B) Resist obtained after exposure and development The etchant penetrates from the interface between the substrate and the shadow mask material, and a predetermined opening shape cannot be obtained. (C) The thickness of the resist obtained from the photosensitive composition comprising casein and dichromate is 5 to 15 μm. On the other hand, a resist obtained from a commercially available dry film is as thick as 25 to 50 μm, and the resolution is reduced. It was also found that there was a problem that it was difficult to control the etching factor.

In particular, it has been found that it is easy to reduce the film thickness. However, it has been found that reducing the film thickness promotes the problems (a) and (b).

[0012]

Heretofore, there has been a dry film to solve the problems of the photosensitive composition comprising casein and dichromate used in the production of shadow masks. However, when attempting to manufacture a shadow mask using a commercially available dry film, (a) air does not escape completely during thermal lamination and bubbles are formed between the photosensitive coating film and the shadow mask material. Disadvantages (b) Etching liquid penetrates from the interface between the resist and the shadow mask material obtained after exposure and development, and a predetermined opening shape cannot be obtained. (C) Photosensitive composition composed of casein and dichromate The thickness of a resist obtained from a commercially available dry film is as thick as 25 to 50 μm, whereas the resolution is reduced, whereas the thickness of a resist obtained from the same is 5 to 15 μm. There is also a problem that it is difficult to control the etching factor.
In particular, it is easy to reduce the film thickness, but when the film thickness is reduced, there is a problem that the problems (a) and (b) are promoted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to reduce the film thickness and follow the irregularities on the surface of a shadow mask material without entrapping air. An object of the present invention is to provide a dry film that can be laminated and that can greatly improve adhesion, and a method for manufacturing a shadow mask for a color picture tube using the dry film.

[0014]

(1) In a dry film having a photosensitive film provided on a base film, a cushion layer comprising a non-photosensitive film is provided between the base film and the photosensitive film. Provided.

(2) In the dry film of (1), the cushion layer is made of at least one of polyvinyl alcohol and modified polyvinyl alcohol.

(3) In the dry film of (1), the thickness of the photosensitive coating film is 5 to 30 μm.

(4) In the dry film of any of (1) to (3), the thickness of the cushion layer is 5 to 2
It was 5 μm.

(5) In the dry film of (1), the base film is made of a transparent resin film which is easily peeled off from the cushion layer.

(6) In the dry film of (5), the base film was made of polyethylene terephthalate resin.

(7) In the dry film of (1), a protective film was provided on the photosensitive coating film.

(8) A photosensitive coating film is provided on both sides of the shadow mask material, and the photosensitive coating film is exposed through an optical mask having a pattern corresponding to the opening of the shadow mask. After the pattern of the optical mask is baked, the resist is formed of a pattern corresponding to the opening of the shadow mask on both sides of the shadow mask material by developing. A dry film photosensitive coating consisting of a base film and a non-photosensitive coating provided on the base film and a non-photosensitive coating provided on the base film is adhered by heat lamination to a dry film. Exposure of the dry film adhered to both sides of this shadow mask material through an optical mask,
After baking the pattern of the optical mask on the photosensitive coating, the base film was removed, and the cushion layer was removed before or simultaneously with the development.

(9) A photosensitive coating film is provided on both sides of the shadow mask material, and the photosensitive coating film is exposed through an optical mask on which a pattern corresponding to the opening of the shadow mask is formed. A method for manufacturing a shadow mask for a color picture tube, which comprises baking a pattern of the optical mask on a coating film and developing the resist to form a resist having a pattern corresponding to the openings of the shadow mask on both sides of the shadow mask material. On both sides of the base film and a cushion layer comprising a non-photosensitive coating provided on the base film, a photosensitive coating provided on the cushion layer and a protective film provided on the photosensitive coating, Remove the protective film from the dry film made of and adhere the photosensitive coating by heat lamination while exposing the photosensitive coating. Then, the dry film adhered to both surfaces of the shadow mask material is exposed through an optical mask, and after baking the pattern of the optical mask on the photosensitive coating film, the base film is removed and before or simultaneously with development. The cushion layer was removed.

(10) In the method of (8) or (9) for producing a shadow mask for a color picture tube, a dry film is simultaneously adhered to both surfaces of a metal thin plate by thermal lamination.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a dry film which is one embodiment of the present invention. This dry film is a base film 2
0, a cushion layer 21 made of a non-photosensitive coating film provided on the base film 20, and a cushion layer 2
1 and a photosensitive coating film 22 provided thereon.

The base film 20 is made of a transparent resin film, such as a polyethylene terephthalate resin, which has appropriate flexibility and is easily peeled off from the cushion layer 21.

The cushion layer 21 is made of at least one of polyvinyl alcohol and modified polyvinyl alcohol. Its film thickness is suitably from 5 to 25 μm. This is because if the film thickness is less than 5 μm, a sufficient cushioning effect cannot be obtained, and if it exceeds 25 μm, unevenness is likely to occur during thermal lamination described later.

The photosensitive coating film 22 has at least the following (a)
To (c).

(A) Acrylic, methacrylic, or epoxy base polymer having a molecular weight of about 5,000 to 200,000. (B) Polymerization of an ethylenically unsaturated compound such as styrene, acrylic acid, or methacrylic acid. The suitable thickness of the photosensitive coating film 22 is 5 to 30 μm, preferably 5 to 15 μm.

(C) Photopolymerization initiator In contrast to such a dry film, the dry film shown in FIG.
4 are provided.

As shown in FIG. 3A, the dry film is formed by applying a non-photosensitive composition comprising at least one of polyvinyl alcohol and modified polyvinyl alcohol onto a base film 20 and drying the same to form a cushion layer 2.
Form one. Next, as shown in (b), a photosensitive composition containing at least the above-described base polymer, polymerizable monomer and photopolymerization initiator is applied on the cushion layer 21, and dried to form a photosensitive coating. A film 22 is formed.

Thus, the dry film shown in FIG. 1 is obtained. Further, the dry film shown in FIG. 2 is obtained by closely attaching the protective film 24 as shown in FIG. 3 (c).

The manufacture of a shadow mask using the above dry film is performed as follows.

First, on the both sides of the degreased and cleaned shadow mask material, the photosensitive film 22 is provided on the shadow mask material side for the dry film shown in FIG. 1, and the protective film 24 shown in FIG. 2 is provided. As shown in FIG. 4, as shown in FIG.
And dry film 28 is simultaneously laminated (thermal lamination) on both sides of the shadow mask material 27,
The photosensitive coating film 22 is adhered to both surfaces of the shadow mask material 27.

Next, as shown in FIG. 5A, a pair of optical masks 29a in which a pattern corresponding to the opening of the shadow mask is formed on a dry film 28 provided on both sides of the shadow mask material 27. , 29b,
Exposure is performed through a base film 20 and a cushion layer 21 below the base film 20.
2 is printed with a pattern corresponding to the opening of the shadow mask. Next, as shown in (b), the outer base film is peeled off. Then, the exposed cushion layer 21
Then, the photosensitive coating film 22 having the pattern printed thereon is developed, or the removal of the cushion layer 21 and the development of the photosensitive coating film 22 having the pattern printed thereon are simultaneously performed. As shown, the unexposed portions of the photosensitive coating film on which the pattern has been baked are removed, and resists 30a and 30b having patterns corresponding to the openings of the shadow mask are formed on both surfaces of the shadow mask material 27.

Next, an etching solution is sprayed on both surfaces of the shadow mask material 27 on which the resists 30a and 30b are formed, thereby forming openings 31 as shown in FIG. Next, the resists 30a and 30b remaining on both surfaces of the shadow mask material 27 are peeled off and removed, as shown in FIG.
As shown in the figure, the flat mask 32 is manufactured by forming a flat mask.

As described above, when the shadow mask is manufactured using the dry film 28 in which the cushion layer 21 is provided between the base film 20 and the photosensitive coating film 22,
The adhesion of the photosensitive coating film 22 to the shadow mask material 27 can be greatly increased. Also, the photosensitive coating film 22
Even if the thickness is reduced, it is possible to perform lamination without entrainment of air by following irregularities on the surface of the shadow mask material. As a result, a high-quality shadow mask can be easily manufactured without changing the shape of the opening and avoiding a decrease in resolution at the time of exposure. Furthermore, unlike the conventional shadow mask manufacturing, the liquid photosensitive composition is not applied to the shadow mask material, and therefore, the step of directly applying and drying the liquid photosensitive composition can be eliminated. Can be simplified.

Hereinafter, the dry film and a method of manufacturing a shadow mask using the dry film will be described with reference to examples.

A polyethylene terephthalate film having a thickness of 25 μm was used as a base film, and a non-photosensitive composition shown in Table 1 was applied to one surface of the base film by a bar coater, dried, and dried from the non-photosensitive coating. Provided a cushion layer. Further, on the cushion layer, a photosensitive composition shown in Table 2 was applied by a bar coater, and dried to form a photosensitive coating having a thickness of 10 μm, 20 μm, and 30 μm, respectively. Three types of dry films having different thicknesses were formed.

[0040]

[Table 1]

[Table 2] Then, three types of dry films having different thicknesses of the photosensitive coating film are coated on both surfaces of an amber shadow mask material having a surface roughness Ra of 0.5 to 0.6 μm, and the photosensitive coating film is coated on the surface of the shadow mask material. Laminated at 120 ° C. as side.

Thereafter, a pair of optical masks each having a pattern corresponding to the opening of the shadow mask are brought into close contact with the dry film laminated on both sides of the shadow mask material, and the light emitted from the high-pressure mercury lamp is applied to the dry film. 6
Exposure was performed at 0 mJ / cm ² through the base film and the cushion layer below the base film, and a pattern corresponding to the opening of the shadow mask was printed on the photosensitive coating films of the dry film on both sides. After that, peel off the outer base film, then
The exposed cushion layer made of polyvinyl alcohol is sprayed and removed with hot water, and the exposed photosensitive coating is sprayed with a 30% 1% aqueous solution of sodium carbonate as a developing solution for 30 to 50 seconds to remove unexposed portions. Then, a resist having a pattern corresponding to the openings of the shadow mask was formed.

Thereafter, on both surfaces of the shadow mask material on which the resist was formed, a specific gravity of 1.500, a temperature of 70.degree.
A ferric chloride solution containing 0.2% of free hydrochloric acid was sprayed as an etching solution, and the shadow mask material was corroded from both sides to form openings. Thereafter, the resist remaining on both surfaces of the shadow mask material was peeled off with a 3% aqueous solution of caustic soda at 40 ° C., washed with water and dried to form a flat mask.

Table 3 shows the entrainment of air when laminating three types of dry films having different thicknesses of the photosensitive coating, penetration of an etching solution between the shadow mask material and the photosensitive coating, and opening. Uneven hole quality, conventional dry film,
That is, polyethylene terephthalate having a thickness of 25 μm
The results are shown in comparison with a case where three types of photosensitive coating films having the same thickness as described above are directly provided on a base film made of a film without providing a cushion layer.

[0044]

[Table 3] As shown in Table 3, when a cushion layer is provided between the base film and the photosensitive coating film, lamination can be performed without involving air. In addition, sufficient adhesion to the shadow mask material can be obtained, and a shadow mask having excellent uneven quality can be manufactured.

[0045]

According to the present invention, when a shadow mask is manufactured using a dry film in which a cushion layer is provided between a base film and a photosensitive coating film, the adhesiveness to the shadow mask material can be greatly increased, and the photosensitive film can be formed. Even if the thickness of the coating film is reduced, the film can be laminated without entrapping air, following the irregularities of the shadow mask material surface. As a result, a high-quality shadow mask can be easily manufactured without changing the shape of the opening and avoiding a decrease in resolution at the time of exposure. In addition, a photosensitive coating film can be provided without applying a liquid photosensitive composition to a shadow mask material as in the conventional manufacturing of a shadow mask, and the manufacturing process of the shadow mask can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a dry film according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a different dry film according to another embodiment of the present invention.

FIGS. 3A to 3C are diagrams for explaining a method of manufacturing the dry film.

FIG. 4 is a view for explaining a method of laminating the dry film on both surfaces of a shadow mask material.

FIGS. 5A to 5E are views for explaining a method of manufacturing a shadow mask using the dry film.

FIG. 6 is a diagram showing a configuration of a color picture tube.

FIGS. 7A to 7D are views for explaining a conventional method of manufacturing a shadow mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Base film 21 ... Cushion layer 22 ... Photosensitive coating film 24 ... Protective film 27 ... Shadow mask material 28 ... Dry film 29a, 29b ... Optical mask 30a, 30b ... Resist 31 ... Opening

Claims (10)

[Claims] 1. A dry film having a photosensitive film provided on a base film, wherein a cushion layer made of a non-photosensitive film is provided between the base film and the photosensitive film. A dry film characterized by the following. 2. The dry film according to claim 1, wherein the cushion layer is made of at least one of polyvinyl alcohol and modified polyvinyl alcohol. 3. The dry film according to claim 1, wherein the photosensitive coating has a thickness of 5 to 30 μm. 4. The dry film according to claim 1, wherein the thickness of the cushion layer is 5 to 25 μm. 5. The dry film according to claim 1, wherein the base film is made of a transparent resin film which is easily peeled off from the cushion layer. 6. The dry film according to claim 5, wherein the base film is made of polyethylene terephthalate resin. 7. The dry film according to claim 1, wherein a protective film is provided on the photosensitive coating film. 8. A photosensitive coating film is provided on both sides of a shadow mask material, and the photosensitive coating film is exposed through an optical mask having a pattern corresponding to the opening of the shadow mask,
A method of manufacturing a shadow mask for a color picture tube, in which after the pattern of the optical mask is baked on the photosensitive coating film and developed, a resist having a pattern corresponding to the opening of the shadow mask is formed on both surfaces of the shadow mask material. The photosensitivity of a dry film comprising a base film on both sides of the shadow mask material, a cushion layer comprising a non-photosensitive coating film provided on the base film, and a photosensitive coating film provided on the cushion layer The coating film is adhered by heat lamination, the dry film adhered to both sides of the shadow mask material is exposed through the optical mask, and after baking the pattern of the optical mask on the photosensitive coating film, the base film is removed. Removing the cushion layer before or simultaneously with development. -Manufacturing method of shadow mask for picture tube. 9. A photosensitive coating film is provided on both surfaces of a shadow mask material, and the photosensitive coating film is exposed through an optical mask on which a pattern corresponding to the opening of the shadow mask is formed.
A method of manufacturing a shadow mask for a color picture tube, in which after the pattern of the optical mask is baked on the photosensitive coating film and developed, a resist having a pattern corresponding to the opening of the shadow mask is formed on both surfaces of the shadow mask material. On the both sides of the shadow mask material, a base film and a cushion layer made of a non-photosensitive coating film provided on the base film, a photosensitive coating film provided on the cushion layer and the photosensitive coating film The dry film consisting of the provided protective film is adhered to the photosensitive film by thermal lamination while removing the protective film and exposing the photosensitive film, and the dry film adhered to both sides of the shadow mask material Was exposed through the optical mask, and the pattern of the optical mask was baked on the photosensitive coating film. A method of manufacturing a shadow mask for a color picture tube, comprising removing the base film and removing the cushion layer before or simultaneously with the development. 10. The method for producing a shadow mask for a color picture tube according to claim 8, wherein a dry film is simultaneously adhered to both surfaces of the shadow mask material by thermal lamination.